% MATLAB SAMPLE: list-serve email and posted on 293 home page
% by Andy Ruina on 9/20/96
%
% Here is a script file that contains some MATLAB samples:
% Loops, (FOR and WHILE)
% overlayed plots (PLOT and HOLD), and
% picking out the last element of a vector (LENGTH).
%
% This is not a solution to HW4.
% It contains stuff which might be useful for HW4.
% To get more documentation on the commands used here
% use MATLAB help or, say, Pratap's book.
%
% This file runs as written. Try it. Understand it. Change it.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% A SIMPLE 'FOR' LOOP. See, eg., Pratap pg 92.
x=0;
for i=0:.5:5
x=x+i; % the usual weird use of '=' in computer programs
end
x % reports the sum 0 + .5 + 1 + 1.5 + ... + 5
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% SAVING PARTIAL RESULTS
z=0; ztemp=0;
for i=0:.5:5
ztemp = ztemp +i;
z= [z;ztemp]; %adds a new element to the column z
%For online help type >help punct
%See, eg, Pratap pgs 155 &/or 41-47
end
z % reports the partial sums in a column 'vector':
% 0 , 0 + 0, 0 + 0 + .5, 0 + 0 + .5 + 1, ...
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% A SIMPLE WHILE LOOP (same result as the for loop above. See Pratap pg 93)
y=0; ytemp=0; i=0;
while i <= 5,
ytemp = ytemp +i;
y= [y;ytemp]; %adds a new row (element) to the column y
i=i+.5;
end
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% PICK OFF THE LAST ELEMENT OF A 'VECTOR' (Pratap, pg 10)
zlast = z(length(z))
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% OVERLAY PLOTS see, eg., Pratap pgs 105-108
% OVERLAY PLOTS: method 1
plot(z,y, z, sin(z)) % The plot is accurate.
% Why doesn't it look like a sine wave?
% OVERLAY PLOTS: method 2 (same result as for method 1)
plot(z,y);
hold on % saves the plot for future overwriting.
plot(z,sin(z));
hold off % allows you to make a fresh new plot